Expression of MAGE genes in testicular germ cell tumors.

OBJECTIVES

Some of the MAGE gene family that encode tumor-rejection antigens recognized by cytotoxic T lymphocytes are expressed at the mRNA level in various malignant tumors. However, these genes are silent in normal tissues, except in the testis and placenta. It is therefore important to understand how MAGE gene expression changes with malignant transformation of the testis. We investigated the expression of MAGE-1, -2, -3, and -4 genes at the mRNA level in testicular germ cell tumors.

METHODS

Reverse transcriptase-polymerase chain reaction for MAGE genes was performed using 32 testicular germ cell tumor specimens.

RESULTS

MAGE-1, -2, -3, and -4 mRNA was detected in 16 (72%), 15 (68%), 18 (82%), and 17 (77%) of 22 patients with pure seminoma or mixed type with seminomatous elements. MAGE-1 , -2, -3, and -4 mRNA was found in 2 (20%), 5 (50%), 4 (40%), and 4 (40%) of 10 patients with nonseminomatous germ cell tumor (NSGCT). The expression rate of MAGE-1, -3, and -4 mRNA was significantly higher in patients with seminomatous elements than that in those with NSGCT. MAGE expression did not correlate with disease progression.

CONCLUSIONS

MAGE genes are more preserved in seminoma than in NSGCT. This suggests that seminoma has traits more similar to normal testis than does NSGCT.